Escaping a variable

Draxter has asked for the wisdom of the Perl Monks concerning the following question:

Hi,

I'm trying to escape a variable with the \x special character, so it will be printed as a hex character. I only manage to do this when I statically define variable, for example:

my $foo = "\x4D";

print "$bla";

M
[download]

But when i try to add the \x to an already existing variable, I always get an "Illegal hexadecimal digit '$' ignored" error message:

my $foo = "4D";
my $bar = "\x4D";

print $bar . "\n";

Illegal hexadecimal digit '$' ignored at roman.pl line 10.
4D.
[download]

What am I doing wrong here, and is it solvable?

Thanks,

Eran

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Replies are listed 'Best First'.
Re: Escaping a variable by davido (Cardinal) on Nov 08, 2011 at 09:16 UTC
`my $foo = "4D"; my $bar = "\x4D"; print $bar . "\n";` [download] Doesn't produce `Illegal hexadecimal digit '$' ignored at roman.pl line 10. 4D.` [download] Why don't you please edit your post and include the actual code that is giving you that error message? I suspect I know what it looks like, but it's your job to actually show code that exhibits the problem you're describing. At any rate, hex will, given the string contained in $foo as a parameter, return the base ten integer value 77. Dave	[reply] [d/l] [select]
Re^2: Escaping a variable by Draxter (Initiate) on Nov 08, 2011 at 09:19 UTC
Hi, Sorry, you are right of course. This is what I do: `my $foo = "4D"; my $bar = "\x$foo"; print $bar . "\n"; Illegal hexadecimal digit '$' ignored at roman.pl line 7. 4D` [download]	[reply] [d/l]
Re^3: Escaping a variable by davido (Cardinal) on Nov 08, 2011 at 09:23 UTC
`print hex($foo), "\n";` The output: `77` [download] Dave	[reply] [d/l] [select]
Re^4: Escaping a variable by Draxter (Initiate) on Nov 08, 2011 at 09:35 UTC
Re^5: Escaping a variable by davido (Cardinal) on Nov 08, 2011 at 09:40 UTC
Re^3: Escaping a variable by moritz (Cardinal) on Nov 08, 2011 at 09:24 UTC
use `print hex $foo` instead. See hex. Perl 6 - second systems done right	[reply] [d/l]
Re^4: Escaping a variable by Draxter (Initiate) on Nov 08, 2011 at 09:26 UTC
Re^5: Escaping a variable by davido (Cardinal) on Nov 08, 2011 at 09:27 UTC


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